Personally, I would get a spare button from the floor, and reprogram it to different departments and set it off from a secure hiding spot (For you, it seems as though the AP office would work.) The instructions are on Workbench and I may or may not have gotten a Word document from my old ETL-GE that has every call box code ever used, such as Hoop Hut and Table Top. If I am not mistaken, it's on here too.
I can only imagine the hilarity of watching the cameras as people scramble to find the errant button declaring "Fast service needed in the Hoop Hut. Third request, service level exceeded. Who is responding" on TVS.